Provided is an orally administered agent that is for ruminants and that is not broken down in the rumen by avoiding breakdown resulting from the rumination of ruminants, passes into the lower alimentary tract, and is there broken down and dissolved. The present invention provides an orally administered agent that is for ruminants and of which the specific gravity is 1.17-2.00, the largest particle size and smallest particles size are both in the range of 4-10 mm, and the breaking strength of the smallest particle size portion in the body-temperature environment of ruminants is 0.5-5.0 N. The present invention further provides a method for orally administering a medicine to ruminants and a ruminant feed containing the orally administered agent.
